Systems and methods for monitoring and controlling fuel systems

Abstract

Systems and methods may be provided for monitoring a fuel level of a vehicle. The fuel may be a gaseous fuel, such as natural gas. An electronic control unit may be able to receive a signal from one or more sensors. The electronic control unit may provide a command to drive a fuel gauge to display the fuel level. The electronic control unit may determine the gauge command based on the received signal and a filling compensation scheme. The electronic control unit may be initialized through a user interface. A filling compensation scheme may be selected during initialization. The electronic control unit may be capable of communicating various sensors, gauges, devices, controls and/or other ECUs of varying specifications.

What is claimed is: 
     
       1. A method for monitoring a gaseous fuel level of a fuel tank of a vehicle and compensating the monitored gaseous fuel level, comprising:
 receiving, at an electronic control unit, at least one sensing signal from one or more sensors configured to monitor the gaseous fuel level of the fuel tank; 
 receiving, at the electronic control unit, a selected fuel level compensation scheme chosen from a plurality of fuel level compensation schemes, wherein the selected fuel level compensation scheme includes a first fuel level compensation scheme adapted to determine a compensated gaseous fuel level of the fuel tank based on a reduction in a maximum pressure of the monitored gaseous fuel in the fuel tank since filling and a time duration since a vehicle engine start, the first fuel level compensation scheme being based on a time constant indicative of a length of time that has elapsed after the maximum pressure has been achieved in the fuel tank since filling, and the first fuel level compensation scheme compensates the monitored gaseous fuel level differently (i) when the time duration since the vehicle engine start is less than or equal to the time constant as compared to (ii) when the time duration since the vehicle engine start is greater than the time constant; 
 determining the compensated gaseous fuel level of the fuel tank based on the at least one sensing signal and the selected fuel level compensation scheme; and 
 sending a signal indicative of the compensated gaseous fuel level to a gauge, thereby causing the gauge to display the compensated gaseous fuel level. 
 
     
     
       2. The method of  claim 1 , wherein the one or more sensors include a temperature sensor and a pressure sensor. 
     
     
       3. The method of  claim 1 , wherein the plurality of fuel level compensation schemes include a second fuel level compensation scheme that is based on a pressure compensation factor; or a third fuel level compensation scheme that is based on an ambient temperature. 
     
     
       4. The method of  claim 1 , further comprising monitoring a filter change. 
     
     
       5. The method of  claim 3 , wherein, in the second fuel level compensation scheme, the pressure of the monitored gaseous fuel is modified using the pressure compensation factor, and wherein the pressure compensation factor is determined based at least on one or more of a maximum filling pressure, an ambient temperature compensated pressure, or a pressure threshold value. 
     
     
       6. The method of  claim 1 , wherein the one or more sensors are configured to monitor the condition of the fuel tank as gaseous fuel is being filled into the fuel tank. 
     
     
       7. The method of  claim 1 , wherein the one or more sensors are configured to monitor the condition of the fuel tank prior to operation of the vehicle that is powered by the fuel tank. 
     
     
       8. The method of  claim 1 , wherein the one or more sensors are disposed within the fuel tank without being disposed on one or more supply lines leading into the fuel tank. 
     
     
       9. The method of  claim 1 , wherein the gaseous fuel comprises natural gas or compressed natural gas (CNG). 
     
     
       10. The method of  claim 1 , wherein the time constant is input to the electronic control unit by a user. 
     
     
       11. The method of  claim 1 , wherein the time constant is a default value stored in the electronic control unit. 
     
     
       12. The method of  claim 1 , wherein one or more of the plurality of fuel level compensation schemes comprises logic that compensates for non-linearity of gas compressibility within the fuel tank. 
     
     
       13. The method of  claim 1 , wherein one or more of the plurality of fuel level compensation schemes comprises logic that is not based on ideal gas law. 
     
     
       14. The method of  claim 12 , wherein the non-linearity of gas compressibility is compensated with aid of one or more look-up tables. 
     
     
       15. The method of  claim 14 , wherein the one or more look-up tables are experimentally determined for different types of fuel tanks, different types of sensors, and the maximum pressure(s) associated with the different types of fuel tanks. 
     
     
       16. The method of  claim 1 , wherein the one or more sensors comprises a dynamic temperature sensor configured to improve a timing resolution and/or accuracy of the compensated gaseous fuel level.